/*

 * Copyright (c) 1998, 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

#ifndef SHARE_VM_OOPS_CPCACHEOOP_HPP

#define SHARE_VM_OOPS_CPCACHEOOP_HPP

#include "interpreter/bytecodes.hpp"

#include "memory/allocation.hpp"

#include "utilities/array.hpp"

class PSPromotionManager;

// A ConstantPoolCacheEntry describes an individual entry of the constant

// pool cache. There's 2 principal kinds of entries: field entries for in-

// stance & static field access, and method entries for invokes. Some of

// the entry layout is shared and looks as follows:

//

// bit number |31                0|

// bit length |-8--|-8--|---16----|

// --------------------------------

// _indices   [ b2 | b1 |  index  ]  index = constant_pool_index

// _f1        [  entry specific   ]  metadata ptr (method or klass)

// _f2        [  entry specific   ]  vtable or res_ref index, or vfinal method ptr

// _flags     [tos|0|F=1|0|0|0|f|v|0 |0000|field_index] (for field entries)

// bit length [ 4 |1| 1 |1|1|1|1|1|1 |-4--|----16-----]

// _flags     [tos|0|F=0|M|A|I|f|0|vf|0000|00000|psize] (for method entries)

// bit length [ 4 |1| 1 |1|1|1|1|1|1 |-4--|--8--|--8--]

// --------------------------------

//

// with:

// index  = original constant pool index

// b1     = bytecode 1

// b2     = bytecode 2

// psize  = parameters size (method entries only)

// field_index = index into field information in holder InstanceKlass

//          The index max is 0xffff (max number of fields in constant pool)

//          and is multiplied by (InstanceKlass::next_offset) when accessing.

// tos    = TosState

// F      = the entry is for a field (or F=0 for a method)

// A      = call site has an appendix argument (loaded from resolved references)

// I      = interface call is forced virtual (must use a vtable index or vfinal)

// f      = field or method is final

// v      = field is volatile

// vf     = virtual but final (method entries only: is_vfinal())

//

// The flags after TosState have the following interpretation:

// bit 27: 0 for fields, 1 for methods

// f  flag true if field is marked final

// v  flag true if field is volatile (only for fields)

// f2 flag true if f2 contains an oop (e.g., virtual final method)

// fv flag true if invokeinterface used for method in class Object

//

// The flags 31, 30, 29, 28 together build a 4 bit number 0 to 8 with the

// following mapping to the TosState states:

//

// btos: 0

// ctos: 1

// stos: 2

// itos: 3

// ltos: 4

// ftos: 5

// dtos: 6

// atos: 7

// vtos: 8

//

// Entry specific: field entries:

// _indices = get (b1 section) and put (b2 section) bytecodes, original constant pool index

// _f1      = field holder (as a java.lang.Class, not a Klass*)

// _f2      = field offset in bytes

// _flags   = field type information, original FieldInfo index in field holder

//            (field_index section)

//

// Entry specific: method entries:

// _indices = invoke code for f1 (b1 section), invoke code for f2 (b2 section),

//            original constant pool index

// _f1      = Method* for non-virtual calls, unused by virtual calls.

//            for interface calls, which are essentially virtual but need a klass,

//            contains Klass* for the corresponding interface.

//            for invokedynamic, f1 contains a site-specific CallSite object (as an appendix)

//            for invokehandle, f1 contains a site-specific MethodType object (as an appendix)

//            (upcoming metadata changes will move the appendix to a separate array)

// _f2      = vtable/itable index (or final Method*) for virtual calls only,

//            unused by non-virtual.  The is_vfinal flag indicates this is a

//            method pointer for a final method, not an index.

// _flags   = method type info (t section),

//            virtual final bit (vfinal),

//            parameter size (psize section)

//

// Note: invokevirtual & invokespecial bytecodes can share the same constant

//       pool entry and thus the same constant pool cache entry. All invoke

//       bytecodes but invokevirtual use only _f1 and the corresponding b1

//       bytecode, while invokevirtual uses only _f2 and the corresponding

//       b2 bytecode.  The value of _flags is shared for both types of entries.

//

// The fields are volatile so that they are stored in the order written in the

// source code.  The _indices field with the bytecode must be written last.

class CallInfo;

class ConstantPoolCacheEntry VALUE_OBJ_CLASS_SPEC {

  friend class VMStructs;

  friend class constantPoolCacheKlass;

  friend class ConstantPool;

  friend class InterpreterRuntime;

 private:

  volatile intx     _indices;  // constant pool index & rewrite bytecodes

  volatile Metadata*   _f1;       // entry specific metadata field

  volatile intx        _f2;       // entry specific int/metadata field

  volatile intx     _flags;    // flags

  void set_bytecode_1(Bytecodes::Code code);

  void set_bytecode_2(Bytecodes::Code code);

  void set_f1(Metadata* f1)                            {

    Metadata* existing_f1 = (Metadata*)_f1; // read once

    assert(existing_f1 == NULL || existing_f1 == f1, "illegal field change");

    _f1 = f1;

  }

  void release_set_f1(Metadata* f1);

  void set_f2(intx f2)                           { assert(_f2 == 0 || _f2 == f2,            "illegal field change"); _f2 = f2; }

  void set_f2_as_vfinal_method(Method* f2)     { assert(_f2 == 0 || _f2 == (intptr_t) f2, "illegal field change"); assert(is_vfinal(), "flags must be set"); _f2 = (intptr_t) f2; }

  int make_flags(TosState state, int option_bits, int field_index_or_method_params);

  void set_flags(intx flags)                     { _flags = flags; }

  bool init_flags_atomic(intx flags);

  void set_field_flags(TosState field_type, int option_bits, int field_index) {

    assert((field_index & field_index_mask) == field_index, "field_index in range");

    set_flags(make_flags(field_type, option_bits | (1 << is_field_entry_shift), field_index));

  }

  void set_method_flags(TosState return_type, int option_bits, int method_params) {

    assert((method_params & parameter_size_mask) == method_params, "method_params in range");

    set_flags(make_flags(return_type, option_bits, method_params));

  }

  bool init_method_flags_atomic(TosState return_type, int option_bits, int method_params) {

    assert((method_params & parameter_size_mask) == method_params, "method_params in range");

    return init_flags_atomic(make_flags(return_type, option_bits, method_params));

  }

 public:

  // specific bit definitions for the flags field:

  // (Note: the interpreter must use these definitions to access the CP cache.)

  enum {

    // high order bits are the TosState corresponding to field type or method return type

    tos_state_bits             = 4,

    tos_state_mask             = right_n_bits(tos_state_bits),

    tos_state_shift            = BitsPerInt - tos_state_bits,  // see verify_tos_state_shift below

    // misc. option bits; can be any bit position in [16..27]

    is_field_entry_shift       = 26,  // (F) is it a field or a method?

    has_method_type_shift      = 25,  // (M) does the call site have a MethodType?

    has_appendix_shift         = 24,  // (A) does the call site have an appendix argument?

    is_forced_virtual_shift    = 23,  // (I) is the interface reference forced to virtual mode?

    is_final_shift             = 22,  // (f) is the field or method final?

    is_volatile_shift          = 21,  // (v) is the field volatile?

    is_vfinal_shift            = 20,  // (vf) did the call resolve to a final method?

    // low order bits give field index (for FieldInfo) or method parameter size:

    field_index_bits           = 16,

    field_index_mask           = right_n_bits(field_index_bits),

    parameter_size_bits        = 8,  // subset of field_index_mask, range is 0..255

    parameter_size_mask        = right_n_bits(parameter_size_bits),

    option_bits_mask           = ~(((-1) << tos_state_shift) | (field_index_mask | parameter_size_mask))

  };

  // specific bit definitions for the indices field:

  enum {

    cp_index_bits              = 2*BitsPerByte,

    cp_index_mask              = right_n_bits(cp_index_bits),

    bytecode_1_shift           = cp_index_bits,

    bytecode_1_mask            = right_n_bits(BitsPerByte), // == (u1)0xFF

    bytecode_2_shift           = cp_index_bits + BitsPerByte,

    bytecode_2_mask            = right_n_bits(BitsPerByte)  // == (u1)0xFF

  };

  // Initialization

  void initialize_entry(int original_index);     // initialize primary entry

  void initialize_resolved_reference_index(int ref_index) {

    assert(_f2 == 0, "set once");  // note: ref_index might be zero also

    _f2 = ref_index;

  }

  void set_field(                                // sets entry to resolved field state

    Bytecodes::Code get_code,                    // the bytecode used for reading the field

    Bytecodes::Code put_code,                    // the bytecode used for writing the field

    KlassHandle     field_holder,                // the object/klass holding the field

    int             orig_field_index,            // the original field index in the field holder

    int             field_offset,                // the field offset in words in the field holder

    TosState        field_type,                  // the (machine) field type

    bool            is_final,                     // the field is final

    bool            is_volatile,                 // the field is volatile

    Klass*          root_klass                   // needed by the GC to dirty the klass

  );

  void set_method(                               // sets entry to resolved method entry

    Bytecodes::Code invoke_code,                 // the bytecode used for invoking the method

    methodHandle    method,                      // the method/prototype if any (NULL, otherwise)

    int             vtable_index                 // the vtable index if any, else negative

  );

  void set_interface_call(

    methodHandle method,                         // Resolved method

    int index                                    // Method index into interface

  );

  void set_method_handle(

    constantPoolHandle cpool,                    // holding constant pool (required for locking)

    const CallInfo &call_info                    // Call link information

  );

  void set_dynamic_call(

    constantPoolHandle cpool,                    // holding constant pool (required for locking)

    const CallInfo &call_info                    // Call link information

  );

  // Common code for invokedynamic and MH invocations.

  // The "appendix" is an optional call-site-specific parameter which is

  // pushed by the JVM at the end of the argument list.  This argument may

  // be a MethodType for the MH.invokes and a CallSite for an invokedynamic

  // instruction.  However, its exact type and use depends on the Java upcall,

  // which simply returns a compiled LambdaForm along with any reference

  // that LambdaForm needs to complete the call.  If the upcall returns a

  // null appendix, the argument is not passed at all.

  //

  // The appendix is *not* represented in the signature of the symbolic

  // reference for the call site, but (if present) it *is* represented in

  // the Method* bound to the site.  This means that static and dynamic

  // resolution logic needs to make slightly different assessments about the

  // number and types of arguments.

  void set_method_handle_common(

    constantPoolHandle cpool,                    // holding constant pool (required for locking)

    Bytecodes::Code invoke_code,                 // _invokehandle or _invokedynamic

    const CallInfo &call_info                    // Call link information

  );

  // invokedynamic and invokehandle call sites have two entries in the

  // resolved references array:

  //   appendix   (at index+0)

  //   MethodType (at index+1)

  enum {

    _indy_resolved_references_appendix_offset    = 0,

    _indy_resolved_references_method_type_offset = 1,

    _indy_resolved_references_entries

  };

  Method*      method_if_resolved(constantPoolHandle cpool);

  oop        appendix_if_resolved(constantPoolHandle cpool);

  oop     method_type_if_resolved(constantPoolHandle cpool);

  void set_parameter_size(int value);

  // Which bytecode number (1 or 2) in the index field is valid for this bytecode?

  // Returns -1 if neither is valid.

  static int bytecode_number(Bytecodes::Code code) {

    switch (code) {

      case Bytecodes::_getstatic       :    // fall through

      case Bytecodes::_getfield        :    // fall through

      case Bytecodes::_invokespecial   :    // fall through

      case Bytecodes::_invokestatic    :    // fall through

      case Bytecodes::_invokehandle    :    // fall through

      case Bytecodes::_invokedynamic   :    // fall through

      case Bytecodes::_invokeinterface : return 1;

      case Bytecodes::_putstatic       :    // fall through

      case Bytecodes::_putfield        :    // fall through

      case Bytecodes::_invokevirtual   : return 2;

      default                          : break;

    }

    return -1;

  }

  // Has this bytecode been resolved? Only valid for invokes and get/put field/static.

  bool is_resolved(Bytecodes::Code code) const {

    switch (bytecode_number(code)) {

      case 1:  return (bytecode_1() == code);

      case 2:  return (bytecode_2() == code);

    }

    return false;      // default: not resolved

  }

  // Accessors

  int indices() const                            { return _indices; }

  int constant_pool_index() const                { return (indices() & cp_index_mask); }

  Bytecodes::Code bytecode_1() const             { return Bytecodes::cast((indices() >> bytecode_1_shift) & bytecode_1_mask); }

  Bytecodes::Code bytecode_2() const             { return Bytecodes::cast((indices() >> bytecode_2_shift) & bytecode_2_mask); }

  Method* f1_as_method() const                   { Metadata* f1 = (Metadata*)_f1; assert(f1 == NULL || f1->is_method(), ""); return (Method*)f1; }

  Klass*    f1_as_klass() const                  { Metadata* f1 = (Metadata*)_f1; assert(f1 == NULL || f1->is_klass(), ""); return (Klass*)f1; }

  bool      is_f1_null() const                   { Metadata* f1 = (Metadata*)_f1; return f1 == NULL; }  // classifies a CPC entry as unbound

  int       f2_as_index() const                  { assert(!is_vfinal(), ""); return (int) _f2; }

  Method* f2_as_vfinal_method() const            { assert(is_vfinal(), ""); return (Method*)_f2; }

  int  field_index() const                       { assert(is_field_entry(),  ""); return (_flags & field_index_mask); }

  int  parameter_size() const                    { assert(is_method_entry(), ""); return (_flags & parameter_size_mask); }

  bool is_volatile() const                       { return (_flags & (1 << is_volatile_shift))       != 0; }

  bool is_final() const                          { return (_flags & (1 << is_final_shift))          != 0; }

  bool is_forced_virtual() const                 { return (_flags & (1 << is_forced_virtual_shift)) != 0; }

  bool is_vfinal() const                         { return (_flags & (1 << is_vfinal_shift))         != 0; }

  bool has_appendix() const                      { return (_flags & (1 << has_appendix_shift))      != 0; }

  bool has_method_type() const                   { return (_flags & (1 << has_method_type_shift))   != 0; }

  bool is_method_entry() const                   { return (_flags & (1 << is_field_entry_shift))    == 0; }

  bool is_field_entry() const                    { return (_flags & (1 << is_field_entry_shift))    != 0; }

  bool is_byte() const                           { return flag_state() == btos; }

  bool is_char() const                           { return flag_state() == ctos; }

  bool is_short() const                          { return flag_state() == stos; }

  bool is_int() const                            { return flag_state() == itos; }

  bool is_long() const                           { return flag_state() == ltos; }

  bool is_float() const                          { return flag_state() == ftos; }

  bool is_double() const                         { return flag_state() == dtos; }

  bool is_object() const                         { return flag_state() == atos; }

  TosState flag_state() const                    { assert((uint)number_of_states <= (uint)tos_state_mask+1, "");

                                                   return (TosState)((_flags >> tos_state_shift) & tos_state_mask); }

  // Code generation support

  static WordSize size()                         { return in_WordSize(sizeof(ConstantPoolCacheEntry) / HeapWordSize); }

  static ByteSize size_in_bytes()                { return in_ByteSize(sizeof(ConstantPoolCacheEntry)); }

  static ByteSize indices_offset()               { return byte_offset_of(ConstantPoolCacheEntry, _indices); }

  static ByteSize f1_offset()                    { return byte_offset_of(ConstantPoolCacheEntry, _f1); }

  static ByteSize f2_offset()                    { return byte_offset_of(ConstantPoolCacheEntry, _f2); }

  static ByteSize flags_offset()                 { return byte_offset_of(ConstantPoolCacheEntry, _flags); }

#if INCLUDE_JVMTI

  // RedefineClasses() API support:

  // If this ConstantPoolCacheEntry refers to old_method then update it

  // to refer to new_method.

  // trace_name_printed is set to true if the current call has

  // printed the klass name so that other routines in the adjust_*

  // group don't print the klass name.

  bool adjust_method_entry(Method* old_method, Method* new_method,

         bool * trace_name_printed);

  bool check_no_old_or_obsolete_entries();

  bool is_interesting_method_entry(Klass* k);

#endif // INCLUDE_JVMTI

  // Debugging & Printing

  void print (outputStream* st, int index) const;

  void verify(outputStream* st) const;

  static void verify_tos_state_shift() {

    // When shifting flags as a 32-bit int, make sure we don't need an extra mask for tos_state:

    assert((((u4)-1 >> tos_state_shift) & ~tos_state_mask) == 0, "no need for tos_state mask");

  }

};

// A constant pool cache is a runtime data structure set aside to a constant pool. The cache

// holds interpreter runtime information for all field access and invoke bytecodes. The cache

// is created and initialized before a class is actively used (i.e., initialized), the indivi-

// dual cache entries are filled at resolution (i.e., "link") time (see also: rewriter.*).

class ConstantPoolCache: public MetaspaceObj {

  friend class VMStructs;

  friend class MetadataFactory;

 private:

  int             _length;

  ConstantPool* _constant_pool;                // the corresponding constant pool

  // Sizing

  debug_only(friend class ClassVerifier;)

  // Constructor

  ConstantPoolCache(int length, const intStack& inverse_index_map,

                    const intStack& invokedynamic_references_map) :

                                        _length(length), _constant_pool(NULL) {

    initialize(inverse_index_map, invokedynamic_references_map);

    for (int i = 0; i < length; i++) {

      assert(entry_at(i)->is_f1_null(), "Failed to clear?");

    }

  }

  // Initialization

  void initialize(const intArray& inverse_index_map, const intArray& invokedynamic_references_map);

 public:

  static ConstantPoolCache* allocate(ClassLoaderData* loader_data, int length,

                                     const intStack& inverse_index_map,

                                     const intStack& invokedynamic_references_map, TRAPS);

  bool is_constantPoolCache() const { return true; }

  int length() const                             { return _length; }

 private:

  void set_length(int length)                    { _length = length; }

  static int header_size()                       { return sizeof(ConstantPoolCache) / HeapWordSize; }

  static int size(int length)                    { return align_object_size(header_size() + length * in_words(ConstantPoolCacheEntry::size())); }

 public:

  int size() const                               { return size(length()); }

 private:

  // Helpers

  ConstantPool**        constant_pool_addr()   { return &_constant_pool; }

  ConstantPoolCacheEntry* base() const           { return (ConstantPoolCacheEntry*)((address)this + in_bytes(base_offset())); }

  friend class constantPoolCacheKlass;

  friend class ConstantPoolCacheEntry;

 public:

  // Accessors

  void set_constant_pool(ConstantPool* pool)   { _constant_pool = pool; }

  ConstantPool* constant_pool() const          { return _constant_pool; }

  // Fetches the entry at the given index.

  // In either case the index must not be encoded or byte-swapped in any way.

  ConstantPoolCacheEntry* entry_at(int i) const {

    assert(0 <= i && i < length(), "index out of bounds");

    return base() + i;

  }

  // Code generation

  static ByteSize base_offset()                  { return in_ByteSize(sizeof(ConstantPoolCache)); }

  static ByteSize entry_offset(int raw_index) {

    int index = raw_index;

    return (base_offset() + ConstantPoolCacheEntry::size_in_bytes() * index);

  }

#if INCLUDE_JVMTI

  // RedefineClasses() API support:

  // If any entry of this ConstantPoolCache points to any of

  // old_methods, replace it with the corresponding new_method.

  // trace_name_printed is set to true if the current call has

  // printed the klass name so that other routines in the adjust_*

  // group don't print the klass name.

  void adjust_method_entries(Method** old_methods, Method** new_methods,

                             int methods_length, bool * trace_name_printed);

  bool check_no_old_or_obsolete_entries();

  void dump_cache();

#endif // INCLUDE_JVMTI

  // Deallocate - no fields to deallocate

  DEBUG_ONLY(bool on_stack() { return false; })

  void deallocate_contents(ClassLoaderData* data) {}

  bool is_klass() const { return false; }

  // Printing

  void print_on(outputStream* st) const;

  void print_value_on(outputStream* st) const;

  const char* internal_name() const { return "{constant pool cache}"; }

  // Verify

  void verify_on(outputStream* st);

};

#endif // SHARE_VM_OOPS_CPCACHEOOP_HPP